TRP-Specific Uplink Timing Advance via CORESET-Guided Access
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Solution Overview
Problem
Existing mobile communication systems face challenges in efficiently acquiring and managing TRP-specific timing advances (TAs) due to implementation complexity and inefficiencies in the random access process, particularly in non-ideal backhaul environments, leading to potential inaccuracies in uplink timing adjustments.
Innovation Solution
A method involving the reception of configuration information for multiple control resource sets (CORESETs) and downlink control information (DCI) from a base station, initiating a random access procedure based on PDCCH orders, and utilizing synchronization signal block indices to obtain TRP-specific TAs, enabling efficient acquisition and management of timing advances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single timing advance (TA) value is supported for a timing advance group (TAG) in existing LTE and NR standards, then the system maintains simplicity in timing management, but it becomes impossible to compensate for timing differences between multiple transmission reception points (TRPs) with large distance differences
Solution Approach 1:
The patent segments the single TAG into multiple TAGs (first TAG and second TAG), each associated with a different TRP. This allows independent TA management for each TRP, enabling accurate timing compensation for multiple TRPs with large distance differences while maintaining manageable complexity through structured segmentation.
Solution Approach 2:
The patent introduces a new dimension by associating each TAG with a specific CORESET pool index (first CORESET pool index for first TAG, second CORESET pool index for second TAG). This dimensional association enables the system to track and manage TRP-specific TAs through the existing CORESET pool index framework without requiring entirely new management mechanisms.
2Measurement precision
If new configurations and operations are defined to obtain TRP specific TAs, then TRP-specific timing accuracy can be achieved, but terminal and base station implementation complexity increases
Solution Approach 1:
The patent makes the existing random access procedure multi-functional by enabling it to serve both traditional purposes and TRP-specific TA acquisition. Through PDCCH order-based random access triggered by DCI, the system can initiate random access procedures that specifically target TRP 1 or TRP 2 based on which TAG's time alignment timer has expired, eliminating the need for separate TRP-specific random access mechanisms.
Solution Approach 2:
The system uses its own existing resources (PDCCH orders, DCI messages, random access procedures) to solve the TRP-specific TA acquisition problem. The base station triggers appropriate random access procedures using PDCCH orders when time alignment timers expire, and the UE self-manages the selection of which TAG to refresh based on timer expiration, reducing implementation complexity.
3Ease of operation
If the terminal randomly selects an SSB index when the Time Alignment Timer expires, then the random access procedure can be initiated, but the terminal may select an SSB index associated with a different TRP, making it difficult to obtain the correct TRP-specific TA
Solution Approach 1:
The patent applies preliminary action by having the base station pre-configure multiple TAGs with different time alignment timers and associate them with different CORESET pool indexes before random access is needed. When a time alignment timer expires, the UE knows in advance which TAG is affected and can initiate the appropriate random access procedure triggered by a PDCCH order, rather than randomly selecting an SSB index.
Solution Approach 2:
The system implements feedback through the PDCCH order mechanism. When the base station detects that a time alignment timer has expired, it sends a PDCCH order with DCI to trigger a random access procedure specifically for that TRP. This feedback loop ensures the UE initiates random access with the correct TRP context, obtaining accurate TRP-specific TA rather than relying on random SSB selection.
Data Source
AI summary
A method performed by a terminal in a wireless communication system according to an embodiment disclosed herein comprises the steps of: receiving configuration information related to a plurality of control resource sets (CORESETs) from a base station; receiving downlink control information (DCI) from the base station; transmitting a random access preamble to the base station; and receiving a random access response (RAR) from the base station. The random access preamble is transmitted on the basis of an SSB index, and the SSB index is related to a first CORESET pool index or a second CORESET pool index.